Thursday, October 28, 2010

Powerful Pollinators, Wild Bees May Favor Eco-Farms

Ben Harder for National Geographic News

Updated October 28, 2004

Organic farming is not only friendlier to the soil and the environment
than conventional farming, it's also friendlier to an underappreciated
agricultural workforcewild bees. So indicates research on how well
bees distribute pollen across different types of cropland.

The finding has economic implications for farmers, many of whom currently rely heavily on domesticated bees to perform crop pollination, Princeton University conservation biologist Claire Kremen told National Geographic News.

If farmers restored natural habitats near their lands and used more organic cultivating techniques, resulting growth of wild bee communities might reduce growers' dependence on European honeybees, the domesticated variety, and ultimately pay financial dividends, she said.

Kremen added that such farming methods would also offer insurance against the possibility of further declines among European honeybees, which have suffered setbacks in recent years. Pesticides, diseases, and other deadly agents have taken their toll over the past decade.

Furthermore, domesticated colonies that have crossbred with Africanized "killer" bees have been rendered too aggressive for beekeepers to manage, further depleting their availability to farmers, said bee researcher Robbin W. Thorp of the University of CaliforniaDavis.

"Pollination is an incredibly important ecological function," Kremen said. Bees function as pollinators because, as they feed on flower after flower, they unintentionally shuttle grains of pollen from one plant to the next. Without bees to do that lifting, many common North American plantsincluding numerous economically important cropswould go unfertilized and would be unable to reproduce, she said.

For more than a century, the most popular pollinators among North American farmers have been domesticated descendants of imported European honeybees, said Thorp. He estimated that 3,500 to 4,000 species of non-domesticated bees that are native to North America can also pollinate cropswhen they can survive on or near croplands.

But modern intensive farming practices often don't provide all the resources bees need to stay alive. Beekeepers take care of domesticated bees, while the wild bees are left to subsist on shrinking wild habitats.

Homegrown Labor Movement

"We don't necessarily need to rely on honeybees," said Kremen. In fact, she said, farms with sufficient numbers and types of wild native bees theoretically don't require the domesticated honeybees at all. "But the caveat is that we only find sufficient numbers of native bees in areas that are near native habitat."

Kremen reached that conclusion after she, Thorp, and Neal Williams of Princeton Unversity conducted experiments on watermelon plots in California. The research trio considered two important factors about each plot: How much natural habitat existed near the farm, and whether the farm relied on organic or conventional cultivating techniques.